My step-daughter has an iMac with OS X Lion. She has an account that auto logs in, with no password on it. Previously, we'd been using the parental controls to keep her from getting up and using the computer in the middle of the night. It was set to limit computer use from 8:30 PM to 8:00 AM. That seemed to work.
My daughter is grounded from computer and video games today. I tried setting the time limits to 8:01 AM to 8:00 AM, but she promptly strolled in and started checking her email and surfing the web. I tried setting it to kick in a couple minutes in the future (10:45 AM to 8:00 AM) and it didn't block the account when 10:45 came around. I tried removing parental controls completely and then adding them back, but that didn't seem to make a difference.
What am I missing? Her account is set as "managed". The clock has the correct time, but, nothing seems to be enforced.